Mechanical pencil



July 23, 1935. P. s. HAUTON MECHANICAL PENCIL Filed Sept. 9, 1931 .llllnlll IIIIIIIIII l,

Patented July 23, 1935 UNIV-TED STATES PATENT OFFICE 1 Claim.

This invention relates to mechanical pencils and their method of production.

The object of the invention is to provide a generally improved and simplified structure which lends itself to economical production and especially to provide an improved threaded feed tube, lead holder and lead manipulating mechanism adapted to be rapidly produced andassembled.

The present invention is related to my copending application, Serial Number 387,542 filedAugust 21, 1929.

In my application Serial Number 387 ,542 I have provided a threaded feed tube or helix consisting of an originally fiat strip of metal, which is coiled so that the strip edges are in contact, the strip being cross-sectionally formed to provide a longitudinal offset in the strip of metal to form a thread, the edges of the strip being primarily maintained in contact with each other by snugly fitting the coiled strip in the longitudinal bore of a casing, which is of substantially the same diameter as the tubular member formed from the coiled strip.

Attempts have been heretofore made to eliminate relative movement in the coils of a feed screw or helix, but such coils have either taken' the form of a helically wound Wire tacked to a casing which requires a casing bore of the same diameter as the feedtube or else a coiled strip of comparatively wide material having the successive coils spaced, such Wide spacing hampering the selection of a desired pitch except by employing very thick material and even then permitting relative movement of the coils.

35 The present invention has achieved a rigid threaded feed tube which does not require a .snug t in the casing bore which can be formed'from thin metal and in which the coils are definitely .maintained in fixed relation to each other, and this is achieved by bonding the coils to each other either by flowing solder over the tube or by welding the successive coils to each other.

The present invention also aims to provide an improved method of attaching a slotted rotatable lead holder to an operating member and amethod of forming a winged tubular lead holder and ejecting mechanism for short lead lengths from a fiat strip of material adapted to receive a winged ejecting pin during its formation.

The characteristics and advantages of the invention are further referred to in connection with the following detailed description of the accompanying drawing, which shows certain embodiments of theinvention for the purpose of affording a clear understanding of the underlying (Cl. 1Z0-18) members thereof to those skilled in the art, but

without limiting the invention to such details.

, In said drawing- Fig. 1 is a broken partly fragmentary longitudinal section of a pencil embodying one form 5 of the invention.

Fig. 2 is a longitudinal section of the lower end portion of the pencil showing another operative position of the lead actuating mechanism.

Fig. 3 is a section of a sleeve for guiding a 10 manually operable member at the end of the pencil remote from the writing end. and securing a threaded feed tube to a casing.

Fig. 4 is a perspective view showing a member for guiding a slotted member.

Fig. 5 is 'a fragmentary perspective view of one end of a slotted member. l

Fig. 6 is a detailed view of one form of a threaded feed tube in the process of formation.

Fig. 7 shows another portion of a finished 20 threaded feed tube and showing one method of bonding the coils to form a rigid tube.

Fig. 8 is a perspective view of a lead holder.

Fig. 9 is a section of Fig. 8 on line 9 9.

Fig. 10 is a perspective view of an ejecting pin 25 adapted to be inserted in the lead holder shown in Fig. 8.

Fig. 11 is a partly fragmentary and partly sectional view of another embodiment of the writing end of the pencil. 30

- Fig. 12 is a side elevation of the locking cup used in Fig. 11.

Continuing now by way of a more detailed description it is to be noted that instead of the comparatively thick casing of wood or other ma- 35 terial heretofore used, a thin shell or casing A preferably of some comparatively stiff light weight material, is tapered at the Writing end of the pencil, the material at the tapered end A being slightly thickened to afford a suitable fitting for 40 a lead guide tip and will be more fully described hereinafter in connection with the assembly of the pencil and the operation of the ejecting mechanism.

A threaded -feed tube or helix B is concen- 45 fiat strip of comparatively thin material and of l such width as to provide the desired pitch for the threads as will be readily understood as the description proceeds. It is to be noted that while a at strip is more easily obtained and handled,

nevertheless other shaped strips might be used. This flat strip of material is offset formed by bending up one edge of the material to form the flange B as indicated in Fig. 6 and then tightly coiled in a helical form to form a threaded tubular member, the ange B' forming a thread wall. This tightly coiled member is then coated with solder B" to form the rigid feed tube and bond the coils to each other. While in the illustrated embodiment a coating of solder is used to secure the successive coils in rigid position, the coils might be also bonded by spot or seam welding the contact between the Vsuccessive coils. It is not absolutely essential that the strip be tightly coiled as a loosely coiled strip in which the spaced coils are bridged by a suitable material bonding the coils, is also within the contemplated scope of the invention. The threaded feed tube B thus formed is held in place by a cup-shaped member C frictionally fitting within the upper end of the casing A and having an annular bead C' resting on the top edge of the casing A to maintain the cup-shaped member in proper position. The lower .end of this cup-shaped. member .has an annular depending flange C" 'snugly fitting the outside of the threaded feed tube and secured thereto in any suitable manner as, for instance, by solder. Instead of a depending annular flange or hub as C". an opening in the cup-shaped member might be soldered or otherwise secured to the threaded feed tube although the annular flange or4 'hub as shown is preferable as affording a rmer support. The fit bf .the cup-shaped member on the inside of the casing A and ange C" effectively maintains the threaded feed tube in proper relation to the easing. The upper end of this cup-shaped member above the bead C' may be and preferably is extended upwardly to'l form a bearing for the inverted cup E shown in Fig. 4, to which the slotted lead holder guide l."k

is secured. To simply and eiectively lock the lead holder guide F to the cup E, theholder is formed with upstanding prongs F' which are preferably stamped from the material of the holder and bent outwardly and upwardly to engage prong end receiving openings E' formed in the top wall of the cup E,. and are spaced apart a suilicient distance preferably near the cup periphery so that the laterally projecting portions F" of the prongs have a substantial bearing against the inside of the cup wall. After theupstanding ends F of the prongs are inserted in openings E they are pressed down to overlie the top of the cup as shown in Fig. 1. The slotted lead holder guide F consists of a rotatable tubular member slotted at one side similar to that shown in my copending application Serial Number 387,542 referred to above, and its lower end is guided in the upstanding sleeve G formed in the guide tip Gf which finishes off the pencil at its writing end. In the lead holder guide F a lead holder G shown in Fig. 8 originally consists of a flat blank having oppositely disposed correspondingly formed embossed lugs or ears H and oppositely disposed Acorrespondingly .\formed indents J. When the marginal edges of embossed lugs H are brought into registry with each other by forming a tubular member of the blank as shown in Fig) 8, a wing is formed thereby which is adapted to pass through the slot of slotted feed tube F for feeding the lead holder J relatively to the feed tube by engagement with threads B' on rotation of member E. The tubular lead holder J contains a relatively movablev electing pin K with a wing K projecting through the longitudinal opening formed by the cleared portions J, the wing K' engaging threads of the feed tube B behind the Wing H and so that it normally is near the end T of slot J while the lead holder is feeding a usable piece of lead. When, however, the lead holder J shown in Fig. 8 arrives at a position near the writing end the wing H passes clear of the threads of the threaded feed tube B and strikes the end of sleeve G of the pencil tip; Its further movement toward the pencil tip is arrested and it idles on the end G. Wing K' still being in engagement with the threads-advances the follower K relatively to holder J and elects the small portion of lead still remaining in the lead holder. the lead holder is accomplished by the rotation of the slotted guide F which'in turn is accomplished by the rotation of the cup-shaped member E in any convenient manner, preferably the means for rotating the cup-shaped member E taking the form of a ferrule L which frictionally ts the cup E and may conveniently be extended upwardly at L to receive the eraser M. l

A modied form of assemblage for the guide tip and .casing is shown in Fig. 11 in which the guide tip R is secured to the tapered portion of the casing A by a locking piece, the upper portion o f which is rmly pressed 'into engagement with the tapered portion'of the casing A and the lower portion iirmly pressed into engagement with a correspondingly shaped portion in the tip R.. Y

This last arrangement has several advantages over the construction shown in Fig. 1 which are readily apparent to those skilled in the art. When a tip of the type shown in Fig. ll isused the clutch or wing member H may be arrested by either striking the top of the locking piece or else striking the face of the taper depending on well-understood proportioning of the parts.

The operation of the pencil, which forms the subject of the present invention, will be fully understood by reference to my copending appli-4 cation Serial Number 387,542.

It is claimed:

In a mechanical pencil, a longitudinally slotted receiving tube, a helically slotted turning tube rotatably mounted on saidl receiving tube, a tubular lead'carrier longitudinally slidable within said'receiving tube having a lead receiving lower end, a radial turning lug near the center portion thereof ,adapted to ride in ther helical groove in said turning tube and an axialI slot' therein extending upwards from said lug to near the upper end thereof, of a length substantially the distance between the winds of the helical slot in said turning tube and a lead ejecting rod axially slidable within said tubular lead carrier,

The movement of having a lower lead ejecting end, a turning lug and an aligning extension projecting axially upwardly from said lug within said lead carrying tube above said slot. A

` PAUL S. HAUTON. 

